Parametric Amplifiers for Readout of Low-Temperature Detectors

This project aims to make microwave parametric amplifiers with high gain, large bandwidth, ultra-low noise, and low power dissipation. Our amplifiers are designed to have greatly improved gain characteristics over similar experimental devices.   The amplifiers would enable revolutionary astrophysics instruments with far-infrared photon-counting detectors or high-resolution x-ray microcalorimeters.

Our goal is to build microwave amplifiers with near quantum-limited sensitivity, octave or greater bandwidth, gain > 20 dB for signals of frequency 1 – 10 GHz, and power dissipation less than 1 microwatt at a 100 mK operating temperature, or 1 milliwatt at 4 K. Such amplifiers would find immediate application in efforts to develop far infrared instruments based on Microwave Kinetic Inductance Detectors (MKIDs), or in x-ray microcalorimeters with microwave SQUID amplifier (mSQUID) readout systems.

Existing state-of-the-art broadband HEMT amplifiers used so far for MKID or mSQUID readout have noise temperatures about 1 – 10 K. The noise of HEMTs, while low enough for many applications, limits sensitivity of MKIDs. In addition, the power dissipation of cryogenic HEMTs is not as low as desired in a space-based instrument. The new amplifiers in this project would be of great benefit in high performance instrument concepts involving MKID or mSQUID arrays for astrophysics missions.